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ALEXANDER MUIRHEAD, OF NORVOOD, COUNTY OF SURREY, EHGLAND.

MANUFACTURE OF COMPOUNDS TO BE USED FOR INSULATINGv dc.

SPECEFZCATIQN ferming part of Letters Patent No. 310,957, dated January20, 1885.

Application filed Deccinberfl. 1834. (No specimens.) Patented in EnglandDecember 522, 1853, No 5,835.

To aZZ whom, it may concern.-

Be it known that I, ALEXANDER Morn- HEAD, a subject of the Queen ofGreat Britain, residing at Norwood, in the county of Surrey, in theKingdom of England, have i11- vented a new and useful Improvement inManufacturing of Compounds to be Used for Insulating, Protecting, orAnalogous Purposes, of which the following is a specification.

The use of gutta-percha for insulating and analogous purposes is wellknown; but there are certain difficulties connected with the use of thecommoner qualities which it has hitherto been found impossible toovercome. 'Now, the object of the present invention is to produce, in asimple and economical manner, gutta-percha compounds suitable forinsulating or protecting electrical conductors and for analogouspurposes, by the use of which the difficulties hitherto experienced willbe avoided.

In carrying out my invention with respect to the production of acompound to be used chiefly in the preparation of tape or canvas for theoutside covering of submarine cables, I take the raw gum and dissolveout the guttapercha by means of melted paraffine-wax or otherhydrocarbon, at a temperature not exceeding the boiling-point of thehydrocarbons employed. The higher the temperature at which thepara'lfine is maintained the greater is its solvent power, and Itherefore maintain it at as high atemperature as possible, not exceedingthe limit before mentioned, in order to obtain a solution containing themaximum amount of gutta-percha. The mixture of paraffinc andgotta-percha thus produced may then be treated with hot water or steamin any well known and convenient manuer,to remove the impurities held insuspension; or, preferably,

'it may be treated with bisulphide of carbon according to the methodadopted in the puriiication of refuse grease, wax, and similarmaterials. The purified mixture is then used in the preparation of thetape or canvas for the outside covering of submarine cables. When thegotta-percha is of the lowest quality, I find it desirable to add asmall proportion of sulphur to the paraffine-wax say from about ten tofifteen per cent.-

In order to obtain a tough and more resisting surface, I add to thesolution of guttapercha in paraffine-wax some finely-powdered silicatedcompoundsuch as blownout furnace-slag, or what is known assilicate-cotton or slag-wool.

In carrying out my invention as applied to the coating of electricalconductors, I produce a partially-vulcanized compound from guttaperchaand sulphurized oil, which will be sufficiently plastic to put on thewires by passing them through dies, as in the ordinary mode ofmanufacturing gutta-percha-covered wires.

In preparing this compound I take paraffineoil or other hydrocarbonmixed with bisulphide of carbon, and add thereto chloride of sulphur. Ithen immediately mix the whole in any suitable apparatus with anyvegetable oil containing a large percentage of what are known asglyeerides in organic chemistry, until an effervescent action commences.hen this action has subsided an elastic spongy mass remains. Theproportion of these materials which I find to yield a good product isone hundred parts, by weight, of vegetable oilsay castoroil, which iscomposed largely of glyceridestwcnty-fivc parts ot'bisulphide of carbon,sixteen parts of parafliueoil, and sixteen to twenty parts of liquidchloride or sulphur. The compound thus produced is washed inparafiine-oil, the excess of oil is pressed out in any convenientmanner, and the compound is thoroughly incorporated by hotmixing-rollers with the gotta-percha obtained as above described, or inthe ordinary manner, in any suitable proportions. In practice, however,I find that the proportion of three parts, by weight, of gutta-percha totwo parts, by weight,of oil compound gives good results. The mixturethus formed is subject to a term perature of from 280 to 800 Fahrenheitfor from two to three hours under pressure, when an elastic compoundlike india-rubbcr willbe produced.

This compound,when ground up in varying proportions with the inferiorqualities of gutta percha, which from their brittleness are now uselessfor the purpose, can be passedthrough dies with the wires to be coatedin the usual way; or I may mix the sulphurized oil compound at once withthe inferior quality guttapercha on mixing-rollers, and pass the mixturethrough the covering-machine at a temperature high enough to effect thepartial vulcanization of the gutta-percha.

To produce a cheap material for common purposessuch as coating wires forelectric lightingI may add to the above compound a proportion, accordingto fancy, of purified bitumen. If a harder compound is required, Idissolve in the oil,before treatment with the chloride of sulphur, aquantity of kauri or similar gum in the proportion of thirty parts, byweight, of kauri gum to one hundred parts of oil.

It is advisable,when a purer and more lasting material is desired, tofree the linseed-oil, castor-oil, or whatever oil is used in the aboveprocess, from all impurities before submitting the sameto the action ofchloride OfSlllQhULthG onlyingrcdientsoithe oils essential to theformation of the elastic compound being the glycerides. SometimesIemploystearine a solid glyceride which can be obtained in a pure statecommerciallyin the manufacture of the above elastic compound. A quantityofstearine dissolvedin bisulphide of carbon or othersolvcut is taken andsubjected to the action of either fumes of chloride of sulphur or asolution of chloride of sulphur in either paraflineoil, or in a mixtureof paraffine-oil and bisulphide of carbon,with the assistance ofagitat-i0n,when an elastic compound results similar to that producedfrom the liquid glycerides contained in linseed, castor, and other oils.

Ido not wish to limit this partot' the invention to the use ofstearine.Any of the pn re glycerides extracted from the various oilssuch aslinseed and cast-or oils, animal fats, 8:c'.- will do to form theelastic compound required for admixture with gutta-percha; but I preferto use that obtained from the solid glyceride stearine on account of itshigher insulating property.

I am aware that it is not new to mix with gntta-percha various oxidizedor sulphurized oils which originally contained glycerides along withother compounds in the manufac ture of anclastic compound for electricalpurposes. V r

The compounds formed by using pure glycerides, whether solid or liquid,at the ordinary temperature alone, in the manner above described, Ifindare superior in insulation re sistance to those formed by the similartreatment of oils and fats containing glycerides together with otherbodies.

I claim as my invention 1. The compound to be used for insulating orprotecting electrical conductors, which consists of a purified mixtureof parafiinewax or other hydrocarbons and gutta-percha, substantially asdescribed.

2. The compound to be used for insulating or protecting electricalconductors, which consists of a purified mixture of paraffinewax orother hydrocarbons containing a small proportion of sulphur and guttape1'clia,substantially as described.

3. The compound to be used for insulating or protecting electricalconductors, which consists of a mixture of purified gutta-percha,prepared by dissolving the same out of raw gum by means of paraffine orother hydrocarbons, with sulphurized oil prepared by subjectingvegetable oils, stearine, or other glycerides to the action of chlorideof sulphur, substantially as described.

l. The compound to be used for insulating or protecting electricalconductors, which consists of a mixture of gutta-percha with sulphurizedoil prepared by subjecting vegetable oils, stearine, or other glyceridesto the action of chloride of sulphur, substantially as described.

5. The production of a partly-vulcanized plastic compound for coatingelectrical coir ductors, which consists in dissolving out the rawgutta-percha in melted paraffine-wax or other hydrocarbon at a hightemperature, then purifying the material so obtained, then mixing thesame with sulphurized oil prepared by subjecting vcgetable oils orstearine to the action of chloride of sulphur, and subjecting themixture under pressure to a high pressure for two to three hours,substantially as set forth.

(i. The production of a partly-vulcanized plastic compound for coatingelectrical eonductors, which consists in dissolving out the rawgut-ta-per'cha in melted paraffine-wax or other hydrocarbon at a hightemperature,then purifying the material so obtained, then mixing threeparts thereof, by weight, with two parts of sulphurized oil prepared bysubjecting vegetable oils or stearine to the action of chloride ofsulphur, and then subjecting the mixture to a temperature of from 280 to300 Fahrenheit for from two to three hours under pressure, substantiallyas set forth.

7. In the manufacture of compounds to be used for insulating,protecting, or analogous purposes, dissolving out the gutta-percha fromthe raw material by means of melted paraflinewax or other hydrocarbon ata high tempera" ture, substantially as described.

8. In the manufacture of compounds to be used for insulating,protecting, or analogous purpose, the hereinbefore-described methods ofpurifying the solution of gutta-percha in paraffine-wax employed thereinby treatment of the same with bisulphide of carbon, as set forth.

9. The use of stearine and other pure glycerides in the manufacture ofelastic substitution products formed by the action of chloride ofsulphur upon such bodies, as described.

10. The compound to be used for insulating or protecting electricalconductors, which consists of a mixture of purified gutta-perchaprepared by dissolving the same out of raw gum by means of paraffine orother hydrocarbons with sulphurized oil containing gumkauri, prepared bysubjecting Vegetable oils,

stearine, or other glycerides containing the same to the action ofchloride of sulphur, sub- 5 stantially as described.

11. I11 the manufacture of compounds to be used for insulating,protecting, or analogous purposes, the hereinbefore-described method ofhardening said compound, consisting in 10 adding gum-kauri to the liquidcontaining the soluble glycerides before treatment with chlo ride ofsulphur, substantially as described.

12. The compound to be used for insulating or protecting electricalconductors, which I 5 consists of a mixture of gutta-percha and bitumenwith sulphurized oil prepared by subjecting vegetable oils, stearine, orother glyc erides to the action of chloride of sulphur as

